Method For Manufacturing a Multimaterial Component or Construction

ABSTRACT

A method for manufacturing a multimaterial component or construction, whereby a body is formed in said method of a basic material and at least one piece formed of a wear resistant material being joined to said body at a temperature of not more than 80% of the lowest melting temperature of the materials to be joined. The invention also comprises the use of a multimaterial component or construction manufactured by means of said method.

The present invention relates to manufacturing of multimaterial components or constructions by manufacturing pieces at least of two different materials, said pieces to be joined with each other for providing a multimaterial component or construction.

BACKGROUND

Wear resistant constructions and components are used e.g. in equipment for reducing the size of rock, building or recycling material. In these processes, the material to be crushed, pressed between the components or colliding against the surfaces of the constructions or components, wears the surfaces of the components in the extent depending on the surface pressure of the contacts, velocities, material characteristics of the component surfaces and the physical characteristics of the material to be crushed, like the compressive strength and tribology characteristics. In other words, as well the movement of the material to be crushed with respect to the surfaces of the components as the penetration thereof to the surface of the component has influence on the wear of the component: The material moving with respect to the surfaces of the components causes cutting and grooving, and the material penetrating to the surface produces burrs on the affected area, that as a result of repeated procedure are easily loosened from the surface of the constructions and components by breakage, fatigue or formation of cuttings. The intensity of the wear of the constructions and components in the different portions thereof and generally in the equipment is defined by the geometry of the equipment, motion state of the components and the flow parameters of the material to be crushed.

The effective lifetime of the constructions and components is in general tried to be increased not only by affecting the geometry and internal flow conditions of the equipment, but also particularly by choosing advantageous materials. The tribology characteristics of metallic wear protection materials of prior art are based e.g. on the advantageous alloying of the metals in question, and eventual adding of particles, on manufacturing processes and further treatments thereof, like heat treatments, whereby phases with better resistance of wear phenomena than usual will be formed in their microstructure as a combined effect of all these factors, said phases typically being hard but having often low toughness and fatigue resistance. As also other than tribology characteristics are required from the constructions and components, they usually cannot be manufactured totally of the materials having the microstructure described above. On the other hand, also the controlling of the form of the wear of the constructions and components e.g. for maintaining the geometry and internal flow model of the equipment may require that different portions of the constructions and components are manufactured of materials different from each other.

The methods used in manufacturing multimaterial components must almost without exception be adapted according the requirements of all the materials forming the construction, whereby the characteristics reached by each material fall short of the target level of the respective material, and the best possible performance of the construction or the component will not be reached. Another significant challenge is to maintain the measure and form tolerances of the pieces or portions during the assembly and the following treatments thereof, which will be experienced by the pieces or portions and the boundaries thereof, formed of different materials. Thereby the different behavior of the materials in contact or joined to each other, e.g. different volumetric changes, can cause damage of the constructions and components. A plurality of manufacturing methods will be totally excluded or at least made unreasonably more complicated by the above mentioned requirements, in terms of commercial exploitation.

The methods and wear parts in accordance with Patent publications JP55317731, JP5317732 and JP6079187, on the contrary, are attempting at manufacturing constructions, where the wearing on desired portions is tried to be increased, and thus the form of the surface of the wear parts is tried to be controlled, by placing less wear resistant portions to a body part being more wear resistant.

In the wear parts disclosed in Patent publication JP2001165146, a second material being more wear resistant is joined for controlling the wear form, but only a joining method requiring exact form and measure tolerances is disclosed for manufacturing constructions according to the target, which in terms of cost-efficiency is not reasonable.

Further, Patent publication JP7323238 aims at the most preferred form of wear parts for the assembly of the constructions in terms of functionality by mounting exactly formed wear protection pieces, to the component bodies, whereby the expensive multi-stage manufacturing process of both the body parts and the wear protection pieces cannot be omitted.

Patent publications JP2001269589 and U.S. Pat. No. 6,123,279 disclose wear parts correspondingly aiming at increasing the wear resistance by mounting wear resistant material onto the body of the wear part, but by using the geometrical form-locking connection, as well requiring application of technically demanding and cost-increasing form-giving methods for wear protection materials with difficult workability and formability, like the hard metals according to the latter publication, before the dimensional and form accuracy required for the assembly can be achieved.

Patent publication JP2004160360 also discloses, that the wear resistant part must be formed (grooved) in a certain way for joining, which is not technically and economically profitable for the wear resistant materials to be used in the method in accordance with the Patent.

Patent publication WO 03/099443 A1 discloses a manufacturing method of multimaterial constructions, where wear resistant material or materials are joined to a body part made of machinable material by means of hot isostatic pressing directly with direct diffusion joint or by using powder material added between the body and the wear resistant pieces. The gas-tight encapsulating of the construction required by the method, and the fact that at least a partial machining is generally required for the pieces to be joined, increase the work phases of the component manufacturing and increase the manufacturing costs too much for the utilization of the method to be economically profitable.

DESCRIPTION OF THE INVENTION

By means of the solution in accordance with the present invention, a multimaterial component or construction typically used as a wear part is provided by connecting pieces made with loose dimensional and form requirements into an entity that in all respects will reach the optimal form in terms of functionality not until the use.

More precisely, the manufacturing method in accordance with the invention is characterized by what is stated in the characterizing part of Claim 1, and the use of the multimaterial component or construction manufactured with the method in accordance with the present invention is characterized by what is stated in the characterizing part of Claim 10.

The invention will be described, by means of example, in more detail in the following with reference to the enclosed drawings, in which

FIG. 1A shows a basic material body of a multimaterial component according to the invention,

FIG. 1B is a cross-sectional view along the line A-A of the basic material body of FIG. 1A,

FIG. 2 shows material pieces to be joined to the basic material body of FIGS. 1A and 1B,

FIG. 3A shows pieces of FIGS. 1 and 2 joined with each other into a multimaterial component,

FIG. 3B is a cross-sectional view along the line A-A of the multimaterial component of FIG. 3A,

FIG. 4 shows an alternative basic material body of the multimaterial component according to the invention,

FIG. 5 shows material pieces to be joined to the basic material body of FIG. 4, and

FIG. 6 shows the pieces of FIGS. 4 and 5 joined with each other into a multimaterial component.

A basic material body 1 of a multimaterial component according to the present invention, shown in FIGS. 1A and 1B, comprises a piece formed of the basic material having joining points 2 for the pieces to be joined ready formed at the determined places of the basic material body, said joining points in the example of FIGS. 1A and 1B being cuttings or cavities formed on the surface of the material. The body 1 is made of an iron based (Fe>50%) basic material including a relatively small amount of metal carbides, preferably less than 10%, by means of a manufacturing method suitable for the respective material, typically by casting, into a form comprising the ready joining points 2.

After the primary manufacture of the basic material body 1, and the eventually needed after-treatments or machining, the body is heat treated under suitable process conditions for achieving as profitable mechanical and tribology characteristics as possible for the basic material.

FIG. 2 shows pieces 3, 4 and 5 made of a wear resistant material, being in the example of the Figure manufactured of three different materials, each of the materials having at least partly different characteristics from each other. These pieces 3, 4 and 5 of wear resistant materials are manufactured by means of a manufacturing method well suitable for each material, respectively, like e.g. by casting or some other molten or powder metallurgical method. Pieces 3, 4 and 5 can be manufactured directly to the final form corresponding to their respective joining points, or after the primary manufacturing they can be subjected to simple forming or machining treatments for achieving the final form.

In the solution in accordance with the invention, the pieces 3, 4, and 5 made of wear resistant material are preferably made of an iron based metal alloy having a carbon content of more than 1.9 percentage by weight, hardness more than 50 HRC, preferably more than 54 HRC, and said alloy having in its microstructure a portion of more than 10% of metal carbides with a diameter of more than 3 μm.

In the solution in accordance with the invention, the volumetric portion of the wear resistant material of the multimaterial construction or construction to be manufactured is preferably more than 4%, and the volume of the biggest single piece manufactured of the wear resistant material is preferably not more than 25% of the total volume of the multimaterial component or construction.

After the primary and eventual secondary working processes the wear resistant pieces 3, 4 and 5 are heat treated, eventually at process conditions differing from each other, in order to provide the most profitable mechanical and tribology characteristics for the pieces. Typically, the wear resistant pieces are of iron based alloy including in their microstructure a bigger volumetric portion of hard phases than the basic material, the grain and particle size thereof being preferably bigger than that of the same or the other hard phases present in smaller amounts in the basic material.

Achieving the most advantageous mechanical and tribology characteristics both of the basic material body 1 and the wear resistant pieces 3, 4 and 5, in this connection means that for example the hardening and tempering temperatures of the iron based alloys differing from each other in terms of their carbon content or other alloying elements are chosen depending on the material, so that the hardness and toughness achieved by each of the materials are as advantageous as possible in the object of use in terms of the loading exerted on each part of the multimaterial component.

FIGS. 3A and 3B show the final multimaterial component being formed by joining the wear resistant pieces 3, 4 and 5 to the base material body 1 at optimal points based on the wearing exerted on the multimaterial component and the characteristics of the wear resistant pieces. The wear resistant pieces 3, 4 and 5 have been joined to the basic material body 1 with a process, wherein the wear resistant pieces and the frame do not form a molten pool and wherein, principally but not necessarily, a layer of additional material 6 of a suitable thickness has been provided between the wear resistant pieces and the body, said additional material 6 having formed a joint as well between the basic material body 1 as the wear resistant pieces 3, 4 and 5 and thus joined them all into a combined multimaterial construction. A suitable additional material 6 is capable of forming a joint between all the wear resistant pieces of the multimaterial construction in question and the body made of the basic material, but does not tend to form harmful reaction products either alone or with the joining materials in the circumstances required by the joining process or in the usage conditions of the construction or the component.

Significant for the choice of the additional material 6 besides the characteristics of the materials to be joined is also that the thermodynamical and kinetic restrictions do not prevent the flowing of the additional material, so that although the body and the wear resistant pieces are manufactured with loose measure tolerances, and often with quite unfinished forms, the space between them will be filled totally or almost totally during the joining process. Taking into consideration all the above described restrictions, the welding or joint casting directly with the molten pools corresponding to the structure of the pieces 1, 3, 4 or 5, for example, is not a possible joining method.

The additional material 6 used in the solution according to the invention can advantageously be some suitable adhesive, the most preferable of them including the epoxy based adhesives, mixtures of rubber and epoxy and mixtures of polyurethane and epoxy. Also another totally or partly organic additional material by means of which the mechanical properties corresponding to the typical tolerances of said adhesives (e.g. strength, shear strength, Shore D hardness and toughness) can be achieved, is well suitable for use in the method in accordance with the invention. Alternatively also a metallic or metal based solder alloy, most preferably a nickel or copper based solder or solder alloy, can be used in a process having both a temperature of not more than 80% of the lowest melting point temperature of the materials to be joined and an atmosphere having such partial pressures of gases, which favor the formation of the desired composition, microstructure and mechanical properties in the joint and joining zone. The solution of the invention, however, is not limited to the use of additional material in joining the wear resistant material pieces to the basic material body.

Figures from 4 to 6 show an alternative example of the solution in accordance with the invention, with a basic material body 7 having a conical form. Groovelike cavities 8 for joining the wear resistant pieces 9 have been formed in the basic material body 7 during the manufacturing. The final multimaterial component is formed by joining the wear resistant pieces 9 by means of additional material 10 to the cavities formed in the basic material body 7.

The solution in accordance with the invention, however, is not limited to the use of additional material for joining the wear resistant pieces to the basic material body. The joint can also be provided by joining the pieces with each other e.g. by means of pressure and the resulting material flow, said pressure being generated mechanically or by pressure-carrying medium between the surfaces to be joined, in a process, wherein the temperature in the pieces to be joined is approximately not more than 60% of the lowest melting point temperature of the materials to be joined.

In the solution in accordance with the invention, the principal function of the body material of the wear parts is to carry the mechanical load exposed in use on the components or parts, and to convey it via the supporting surfaces to the frame of the apparatus acting as a mounting base, whereby an adequate strength, toughness and fatigue resistance are required from the material thereof. The function of the wear resistant pieces in said multimaterial constructions and components is principally limited to the wear protection, whereby their characteristics can be chosen almost exclusively according to the characteristics profile required by that function. Thereby the essential requirements are especially the hardness of the material and its ability to resist the propagation of the wear phenomena and the resulting material changes typical of the circumstances of the respective application. While propagating, the wear would typically cause grooving, cratering, burring, cutting or breaking of the construction or component material, but with a properly chosen and processed wear resistant material, the occurring of those phenomena is minor compared with the body material of the construction and the other generally used materials of the application.

For the assembly of the wear resistant construction or component, the basic material body and the wear resistant pieces are cleaned from the affected zones of the surface like oxidation zones, or from impurities like cutting fluid residues caused by the primary manufacturing or the followed working and/or machining, which all can have a deteriorating effect on the characteristics of the joining zone formed in the assembly by the body material, the wear resistant pieces and the additional material. To form a joint, a suitable additional material for the respective material pair, as a layer of a suitable thickness is added between the body and the wear resistant pieces prepared as described above. The parameters of the joining process must be selected so that the characteristics of the additional material in the process conditions enable an adequate wetting of the surfaces to be joined and the additional material flow, so that the space between the body and the wear resistant pieces is filled as perfectly as possible. On the other hand, the conditions must not favor too strong reactions of the additional material with any of the materials imparted in the joining.

In the solution in accordance with the invention, the characteristics of the wear resistant materials and the sizes of the pieces are preferably determined with following formula:

((sum of the volumetric proportions of the wear resistant materials of the volume of the total construction)/5)+((HRC hardness of the wear resistant materials as a weighted average of their volumetric proportions)/10).

Thereby the index to be received from the formula should be bigger than 6 and preferably bigger than 10.

The multimaterial constructions and components manufactured with the method in accordance with the invention are well suitable for use in wear parts in demanding applications like for example in reducing the size of rock, building and/or recycling material.

Among others, the following advantages are provided by the solution in accordance with the present invention:

-   -   (i) By limiting the use of wear resistant material in         constructions and components only to areas, where it is         unavoidable for the part of the wear protection, the         manufacturing costs of the products in question can be         decreased.     -   (ii) The single materials to be joined into a multimaterial         component or construction by means of the solution in accordance         with the invention can be manufactured separately by means of         methods well suitable for their manufacturing, whereby their         desired technical characteristics can be achieved with more         reliability, and as a result, the performance and reliability of         the constructions and components will be improved.     -   (iii) By loosening the dimensional and form tolerances required         by the assembly of the constructions, significant savings can be         achieved.     -   (iv) Through decreased use of wear resistant materials and the         raw materials needed for manufacturing the same, the ecological         efficiency of the constructions and components to be produced         will be improved. 

1. A method for manufacturing a multimaterial component or construction, said method comprising the following steps: forming a body of a basic material, said body comprising at least one joining point at least for one piece formed of wear resistant material, forming of at least one wear resistant iron based material at least one piece to be joined to the body formed of the basic material, joining at least one piece formed of wear resistant iron based material to the body formed of the basic material, joining at least one piece made of wear resistant iron based material to the body formed of basic material at a temperature which is not more than 80% of the lowest melting point temperature of the materials to be joined, wherein the characteristics of the wear resistant iron based materials and the piece sizes are determined with the following formula: ((sum of the volumetric proportions of the wear resistant iron based materials of the volume of the total construction)/5)+((HRC hardness of the wear resistant iron based materials as a weighted average of their volumetric proportions)/10) so that the resulted index is more than 6, preferably more than
 10. 2. A method in accordance with claim 1, wherein the body formed of the basic material is manufactured of an iron based alloy (Fe>50%), wherein the portion of the metal carbides in the microstructure is less than 10%.
 3. A method in accordance with claim 1, wherein at least one piece made of wear resistant iron based material is manufactured of a material having a carbon content of more than 1.9 weight percent, hardness of more than 50 HRC, preferably of more than 54 HRC and the microstructure of said alloy having a portion of more than 10% of metal carbides with a diameter of more than 3 μm.
 4. A method in accordance with claim 1, wherein the volumetric portion of the wear resistant iron based material in the multimaterial component or construction to be manufactured is more than 4%.
 5. A method in accordance with claim 1, wherein the volume of the biggest single piece manufactured of the wear resistant iron based material is not more than 25% of the volume of the whole multimaterial component or construction.
 6. A method in accordance with claim 1, wherein the body formed of the basic material and at least one wear resistant iron based material piece are joined with each other with an additional material.
 7. A method in accordance with claim 6, wherein the additional material is an adhesive.
 8. A method in accordance with claim 6, wherein the additional material is a metallic or metal based material.
 9. Use of a multimaterial component or construction manufactured with a method in accordance with claim 1 in reducing the size of rock, building and/or recycling material. 